adding visual regression testing with percy

package.json

@@ -61,6 +61,7 @@
     "ember-load-initializers": "^2.0.0",
     "ember-maybe-import-regenerator": "^0.1.6",
     "ember-native-dom-helpers": "^0.6.2",
+    "ember-percy": "^1.5.0",
     "ember-qunit": "^4.4.1",
     "ember-resolver": "^5.0.1",
     "ember-sinon": "^2.2.0",

tests/acceptance/visual-regression-test-test.js

@@ -0,0 +1,28 @@
+import { module, test } from 'qunit';
+import { visit } from '@ember/test-helpers';
+import { setupApplicationTest } from 'ember-qunit';
+import { percySnapshot } from 'ember-percy';
+
+async function renderFromToc(tableOfContents, path = "") {
+  for (const item of tableOfContents) {
+    if (!item.pages || item.pages.length === 0) {
+      await visit(path + item.title);
+      await percySnapshot(path + item.title);
+    } else {
+      await renderFromToc(item.pages, `${path + item.title}/`);
+    }
+  }
+}
+
+module('Acceptance | visual regression test', function(hooks) {
+  setupApplicationTest(hooks);
+
+  test(`visiting visual regressions with Percy`, async function(assert) {
+    assert.expect(0);
+    await visit('/');
+
+    let tableOfContents = this.owner.lookup('controller:application').model;
+
+    await renderFromToc(tableOfContents);
+  });
+});